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Russian military exercises near the Ukraine border are raising concerns that Moscow may be putting troops in a position to move across the border if such orders are issued, a senior U.S. official familiar with the most recent administration assessment told CNN on Thursday.

But the United States still believes that Russia doesn't plan to order its forces into tumultuous Ukraine, the official said.

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For now, U.S. officials continue to believe Russian President Vladimir Putin is using the exercises as a message to U.S. and Ukrainian officials that he has the ability to move his military into Ukraine to protect Russian interests if he chooses to do so, the official said.